Gravitational waves discovery gives Nobel prize committee another headache
If confirmed, the detection by physicists of primordial gravitational waves created in the first moments after the big bang, reported on Monday, will go down in the annals of science as a fundamental breakthrough in our understanding of how the universe began.
A team of American astronomers announced that they had detected the tell-tale signature of “cosmic inflation” using an experiment called Bicep2 – a telescope located under the clear skies of the south pole.
For more than 45 years, inflation has been just a theorist’s dream. It is a hypothetical idea used to explain certain characteristics of the universe, in particular why space appears to have more or less the same density of matter everywhere.
The theory postulates that the universe underwent rapid expansion early in its history, doubling its size more than 60 times in the space of less than a second. It is akin to unfolding a crumpled piece of paper. All the wrinkles and defects are smoothed out into a more or less featureless continuum.
If Monday’s result proves to be correct then the Nobel committee will almost certainly start reaching for its gongs. So who is in the frame?
Stephen Hawking’s reaction was aired on Radio 4’s Today programme the morning after. The famous physicist said he had brought together the main protagonists at a workshop in Cambridge in 1982. “At the workshop we established the now accepted picture of inflation in the very early universe,” said Hawking. He also confidently declared victory in a wager with Prof Neil Turok, director of the Perimeter Institute in Canada, over his cyclic universe theory, which predicts no primordial gravitational waves (Turok says the jury is still out).
Hawking may well have been throwing his hat into the ring for a Nobel, but he is by no means a frontrunner. Inflation was developed by a cabal of theorists over a number of years. Despite his contributions, Hawking was not a pioneer. A maximum of three people can share the prize and there are at least half a dozen who have a claim.
The person generally credited with the theory is American physicist Alan Guth. He proposed the idea in 1980. But a few months before, Russian physicist Alexei Starobinsky had published the same idea. They differed in their approaches but both had independently realised that inflation could be an integral part of the universe’s origins.
Neither’s approach worked particularly well, however. Starobinsky was trying to change the laws of physics, and Guth’s model introduced all sorts of weirdness – what Star Trek would call “spatial anomalies” – into the maths.
Enter Andrei Linde. Born and educated in Moscow, he moved to America in 1990. A rather touching YouTube video is doing the rounds in which Bicep2 principal investigator Chao-Lin Kuo takes a bottle of champagne and a video camera to cold-call Linde with the news that they have confirmed inflation. Linde first frowns then needs the news repeating twice before he will believe it.
Linde solved Guth’s anomalies but was not the only person to do so. Americans Andreas Albrecht and Paul Steinhardt independently proposed the solution. In a twist, Steinhardt subsequently lost his faith in inflation even though he, Guth and Linde were awarded the Dirac medal in 2002 for its development.
Then we get to the people who calculated the gravitational waves spectrum that Bicep2 saw. This is where Hawking enters the frame. They also include pioneers Starobinsky, Guth, Steinhardt and others. By now it was 1982, and inflation had permeated the cosmological community. Many were jumping on the bandwagon.
Then you have to add in the experimenters who designed and operated Bicep2. There are four principal investigators alone: John Kovac, Clem Pryke, Jamie Bock and YouTube star Chao-Lin Kuo.
Last year’s physics Nobel was for the Higgs discovery and was only given to theorists, not experimentalists. In the run up to the announcement, it was speculated that the committee might make the third recipient the organisation Cern – the international collaboration that runs the massive Large Hadron Collider on the Swiss-French border, which discovered the Higgs. That didn’t happen. Maybe there is a case this time for choosing two theorists and then the Bicep2 team as a whole.
First, though, for a Nobel to be considered, the discovery must be confirmed. This is not yet a done deal. There are discrepancies between the new announcement and existing observations. So now all eyes are on the European Space Agency’s Planck satellite. The €700m (£590m) mission has returned data about the whole sky, which is currently being analysed for the same signals reported by Bicep2. Planck is expected to report in October.
If it confirms Bicep2’s observations, the 2015 Nobel prize committee will have a tough choice to make.
[“Star Explosion In A Galaxy Of An Unknown Universe” on Shutterstock]